CpG‐ODN‐stimulated dendritic cells act as a potent adjuvant for E7 protein delivery to induce antigen‐specific antitumour immunity in a HPV 16 E7‐associated animal tumour model

Abstract

SUMMARYWe previously reported that both E7 and CpG-oligodeoxynucleotide (ODN) are required for protecting animals from human papillomavirus (HPV) 16 E7-associated tumour challenge. Here we investigate dendritic cells (DC)-based approach in this protection. In the study, we isolated bone marrow-derived DC and stimulated DC with E7 and ODN. In vitro stimulation of DC with E7 plus ODN resulted in more production of interleukin-12, as compared to that with E7 or ODN alone. Further injection with E7+ODN-stimulated DC resulted in more significant tumour protection, as compared to stimulation with E7 or ODN alone. We further evaluated the levels of immune responses induced by DC stimulated with E7+ODN. We observed little enhancement of E7-specific antibody and T helper cell proliferative responses by E7+ODN stimulation, as compared to E7 stimulation. However, there was some enhancement of interferon-c (IFN-c) production from CD4 + T cells and a more significant production of IFN-c from CD8 + T cells by E7+ODN stimulation, as compared to E7 stimulation alone. This was consistent with intracellular IFN-c staining levels of CD8 + T cells. Tumour protection further appeared to be mediated by CD8 + T cells, as determined by in vivo T-cell depletion. Thus, these data suggest that upon ODN stimulation DC might function as a potent adjuvant for E7 protein delivery for induction of protective cellular immunity against HPV E7-associated tumour challenge.

Antitumor Therapeutic Effects of E7 Subunit and DNA Vaccines in an Animal Cervical Cancer Model: Antitumor Efficacy of E7 Therapeutic Vaccines Is Dependent on Tumor Sizes, Vaccine Doses, and Vaccine Delivery Routes

“…This notion is in line with our observation that either injection of E7 proteins or CpG-ODN alone into the tumor sites failed to show such a dramatic therapeutic synergy as intratumoral and subcutaneous injection of E7 proteins combined with CpG-ODN. This is also supported by our previous two reports that in vitro stimulation of DC with CpG-ODN generated a high amount of IL-12 (Kim et al, 2004a) and that direct i.t. injection of IL-12-expressing adenovirus along with recombinant E7 proteins resulted in regression of established tumors of a relatively big size through induction of CTL (Ahn et al, 2003).…”

“…For example, E7 DNA vaccines have been reported to be effective for antitumor protection through induction of antigen-specific CD8 ϩ CTL effector cells Hung et al, 2001Hung et al, , 2002Kim et al, 2003Kim et al, , 2004bKim and Sin, 2005). Similar findings were observed in the case of whole or fusion E7 proteins (Kim et al, 2002;Cui and Huang, 2005;Preville et al, 2005), E7-primed dendritic cells (De Bruijn et al, 1998;Kim et al, 2004a), and bacterial/viral vectors expressing E7 or IL-12 (Lamikanra et al, 2001;Ahn et al, 2003;Bermudez-Humaran et al, 2005), as well as CTL epitopes of E7 (Feltkamp et al, 1993;Vambutas et al, 2005). Recently, we reported that E7 protein plus CpG-oligodeoxynucleotide (ODN) are both required for induction of CD8 ϩ CTL responses, which are required for both prophylactic and therapeutic antitumor protection (Kim et al, 2002).…”

“…Enzyme-linked immunosorbent assay (ELISA) was performed as previously described (Kim et al, 2002(Kim et al, , 2004aAhn et al, 2003). In particular, recombinant E7 protein (1 g/ml in PBS) was used as a coating antigen.…”

mRNA-based cancer vaccine: prevention of B16 melanoma progression and metastasis by systemic injection of MART1 mRNA histidylated lipopolyplexes

“…[53][54][55] The vaccination of mice with DNA encoding sig-E7-LAMP1-16 have generated simultaneous CD4 þ and CD8 þ T-cell responses against the human papillomavirus. [56][57][58] Lastly, the injection of DCs transfected with the telomerase reverse transcriptase-LAMP1 mRNA has led to an enhancement of antigen-specific CD4 þ and CD8 þ T cells against metastatic prostate cancer in humans. 59 In contrast with the above-mentioned data, we found that the injection of sig-MART1-LAMP1 mRNA lipopolyplexes did not protect mice against B16 melanoma, but induction of an anti-MART1 immune response upon a systemic injection of sig-MART1-LAMP1 mRNA in mice has never been reported previously.…”

Inhibitory effects of unmethylated CpG oligodeoxynucleotides on MHC class I‐deficient and ‐proficient HPV16‐associated tumours

“…4,5 Unmethylated oligodeoxynucleotides harboring guanine-cytidine dimers (CpG ODN) that mimic the bacterial DNA are good candidates for such therapeutic agents, since they have been described as potent inducers of the innate and adaptive immune responses, providing the missing ''danger signal'' through the Toll-like receptor 9 (TLR 9) involving pathway. 6 In tumour immunology, CpG ODN have been used in a number of animal studies as adjuvants in experimental vaccinations [7][8][9][10] for ex vivo preparation of cellular vaccines as they induce maturation of dendritic cells [11][12][13] and for the therapy of the residual disease after chemotherapy or tumour resection. 14 Moreover, repeated direct intratumoral administration of CpG ODN significantly inhibited the growth of established tumours in animal models, [15][16][17][18] including the model for human cervical carcinoma.…”